public class e4_20{
  public static void main(String args[]){
    char a[] ={'a','b','c','D','E','F'};
   for(int i =0;i<a.length;i++){
    if(Character.isLowerCase(a[i]))
      a[i]=Character.toUpperCase(a[i]);
    else if(Character.isUpperCase(a[i]))
    a[i]=Character.toLowerCase(a[i]);
   }
   for(int i=0;i<a.length;i++)
   System.out.println(""+a[i]);
}
}
